Learn 2D Game Development with C#: For iOS, Android, Windows Phone, Playstation Mobile and More

285 Pages·2016·7.04 MB·English

by  Pavleas J. et al.

For your convenience Apress has placed some of the front
matter material after the index. Please use the Bookmarks
and Contents at a Glance links to access them.
Contents at a Glance
About the Authors ���������������������������������������������������������������������������������������������������������������xv
About the Technical Reviewer ������������������������������������������������������������������������������������������xvii
Acknowledgments �������������������������������������������������������������������������������������������������������������xix
Introduction �����������������������������������������������������������������������������������������������������������������������xxi
■ Chapter 1: Introducing 2D Game Development in C# ���������������������������������������������������������1
■ Chapter 2: Getting to Know the MonoGame Framework �������������������������������������������������11
■ Chapter 3: 2D Graphics, Coordinates, and Game State ����������������������������������������������������41
■ Chapter 4: Getting Things Moving �����������������������������������������������������������������������������������87
■ Chapter 5: Pixel-accurate collisions������������������������������������������������������������������������������123
■ Chapter 6: Game object states and Semiautonomous Behaviors ����������������������������������147
■ Chapter 7: Sprites, Camera, Action! ������������������������������������������������������������������������������183
■ Chapter 8: Particle Systems ������������������������������������������������������������������������������������������213
■ Chapter 9: Building Your First 2D Game �����������������������������������������������������������������������227
Index ���������������������������������������������������������������������������������������������������������������������������������261
v
Introduction
Welcome to Learn 2D Game Development with C#. Because you have picked up this book, you are likely interested in
creating your own games with the C# programming language. This book teaches you how to develop 2D games with
C# and MonoGame by giving you background and conceptual information so you can play, examine, and develop
2D games.
This book identifies and presents relevant concepts from software engineering, computer graphics, mathematics,
physics, and game development—all in the context of building 2D games. The projects you’ll develop in this book are
based on MonoGame, the open source implementation of of the popular XNA Framework discontinued by Microsoft.
The presentations are tightly integrated with the analysis and development of source code; you’ll spend much of the
book building gamelike concept projects that demonstrate game principles and components. By building on concepts
introduced early on, the book leads you on a journey through which you will master the basic concepts behind game
development while simultaneously gaining hands-on experience developing simple but working 2D games.
By the end of the book, you will be familiar with the implementation details of 2D games, and you should feel
competent in implementing commonly encountered 2D game behaviors using MonoGame.
Who should read this book
This book is targeted toward programmers who are familiar with basic object-oriented programming concepts and
have a basic to intermediate knowledge of an object-oriented programming language like C# or Java. For example,
if you are a student who has taken a few introductory programming courses, an experienced developer who is new to
games and graphics programming, or a self-taught programming enthusiast, you will be able to follow the concepts
and code presented in this book with little trouble. If you’re new to programming in general, it is suggested that you
first become comfortable with the C# programming language before tackling the content provided in this book.
Assumptions
You should be experienced with programming in an object-oriented programming language, such as C# or Java.
The examples in this book were created with the assumption that readers understand data encapsulation and
inheritance. In addition, you should also be familiar with basic data structures such as linked lists and dictionaries
and be comfortable working with the fundamentals of algebra and geometry, particularly linear equations and
coordinate systems.
Who should not read this book
This book is not designed to teach readers how to program, nor does it attempt to explain intricate details of C# or
MonoGame. If you have no prior experience developing software with an object-oriented `programming language,
you will probably find the examples in this book difficult to follow.
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■ IntroduCtIon
On the other hand, if you have an extensive background in game development for other platforms and with
other programming languages, the content here will be too basic; this is a book intended for developers without
2D game development experience.
Organization of this book
This book divides the process of building 2D games into essential topic areas: tools, graphics, special effects, math and
physics, and logic and behavior. These topics are organized into chapters. Each topic area (chapter) is then subdivided
into essential concepts; for example, concepts related to computer graphics include coordinate spaces and camera
abstraction. The book introduces each concept via a gamelike example organized as a section in a chapter. Each
has an associated step-by-step project workflow. In this way, each section in the book corresponds to a single project
or concept.
The first section begins with a simple project that you will build from scratch. Throughout the text, each
subsequent section builds upon the sections that precede it. While this makes it a bit difficult to skip around in the
book, it will give you practical experience and a solid understanding of how the different concepts relate to one
another. In addition, rather than always working with new and minimalistic projects, you gain experience with
building larger and more interesting projects.
The projects themselves start with simple concepts, such as creating objects and moving them across the screen,
but quickly move to more complex concepts, such as implementing pixel-accurate collision detection and working
with user-defined coordinate systems. In this way, while the concepts are presented in simple 2D gamelike examples,
by the end of the book, your code base for the projects will include all the essential concepts covered.
That final code base, which you will have developed incrementally over the course of the entire book, serves as a
great platform on which you can begin building your own 2D games. This is exactly what the very last chapter of the
book does, leading you from conceptualization, to design, to implementation of a not-so-simple casual 2D game.
Finding your best starting point in this book
As a reader, there are several ways for you to follow along with this book. The first and most obvious is to enter the
code into your project as you follow through each step in the book. From a learning perspective, this is probably the
most effective way to absorb the information presented; however, we understand that it may not be the most realistic,
due to the amount of code or debugging that approach may require. To help ameliorate this, each of the sections and
projects in this book has two corresponding source code folders: the starter project in a 1.Starting folder, and the
completed project in a 2.Completed folder. You can see an example of this structure in Figure 1. The starter projects
allow you to follow along in the corresponding section by entering the code as you encounter it in the book, while the
completed project lets you run and see the project in its completed state.
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■ IntroduCtIon
Figure 1. The folder structure for the book projects
We recommend that you refer to the completed project when you begin a new section. Doing so lets you preview
the current section’s project, giving you a clear idea of the end goal, and letting you see what the project is trying
to achieve. You may also find the completed project code useful when you have problems while building the code
yourself, because you can compare your code with the completed project’s code during difficult debugging situations.
■ Note We have found the WinMerge program (http://winmerge.org/) to be an excellent tool for comparing
source code files and folder.
Finally, after completing a project, we recommend that you compare the behavior of your implementation with the
completed-project implementation provided. By doing so, you can observe whether your code is behaving as expected.
Conventions and features in this book
This book presents information using conventions designed to make the information readable and easy to follow:
• Each example is built on top of prior ones; however, complete source code is provided for each
exercise, so you can use that to skip sections you don’t need.
• A screen shot and an outlined overview of the steps involved precede each step-by-step
procedure, so that you will know what to expect.
• When necessary, we provide relevant background information before beginning the analysis of
how to implement the concept. For example, the book discusses differences between pixel and
user-defined spaces before analyzing how to implement a user-defined coordinate system.
xxiii
■ IntroduCtIon
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xxiv
Chapter 1
Introducing 2D Game Development
in C#
C#, a modern object-oriented programming language from Microsoft, is one the easiest languages to develop
applications with. When developing C# applications within the Microsoft Visual Studio Integrated Development
Environment (IDE), programmers are especially empowered with near-transparent application programming
interface (API) access, friendly editor-assisted code completion, and almost instantaneous compilations. For
these reasons, C# is one the best programming languages for prototyping sophisticated ideas and for learning and
experimenting with difficult concepts.
Developing games can be a challenging and lengthy process, partly due to the general programming knowledge
and experience required to begin game development, and partly due to the steep learning curve associated with most
graphics APIs, such as Microsoft Direct3D and OpenGL. The MonoGame Framework, an open source implementation
of the popular XNA Framework discontinued by Microsoft, addresses these issues by creating a developer-friendly
framework with a much shallower learning curve. This framework lets developers quickly learn the information needed
to begin creating 2D games for many of the popular platforms, from machines running Microsoft (Windows 7 or 8),
Apple (Mac OS X), or Linux operating systems to popular mobile devices (iOS, Android, or Windows Phone). The
examples in this book are designed to run on Windows for easy demonstration, but the same core principles apply to 2D
game development on any platform. So once you’ve mastered the basics, you’ll have MonoGame’s cross-platform support
at your fingertips.
The MonoGame framework presents its interface in C#. Together with Microsoft Visual Studio or the
MonoDevelop IDE, it becomes possible to focus on learning 2D game development concepts in C# and avoid being
distracted by the peripheral requirements of computer graphics, input device interactions, or programming language
nuances. For example, instead of working with separate graphical API and User Interface (UI) API for drawing
and receiving input, MonoGame provides a straightforward way of drawing graphical objects to the application
windows and a simple model for receiving player actions. These allow us to concentrate on the structures and logics
for coordinating the drawing of gaming elements and interpreting the intentions of the players rather than being
consumed by the details of converting information between the different APIs.
With the elegant C# programming language, we can take advantage of data abstraction and object inheritance
in modeling game element behaviors while avoiding preoccupation with pointer manipulation or memory
management. Best of all, with MonoGame being an open source project and C# being freely available for the general
public, it is not only relatively straightforward, but also free to build games for multiple platforms. Since many vendors
(e.g., Windows Marketplace, or Google play) encourage hobbyists to self-publish applications and games, it becomes
possible to build, perfect, and eventually publish games in the marketplace!
This chapter first leads you through the steps of downloading, installing, and setting up the development
environment: Visual Studio Express IDE, MonoGame framework, and XNB Builder. We then describe the coverage of
2D game development topics in the rest of this book, with brief discussions of related topics that are not covered and
where interested readers can find additional information on them.
1
Chapter 1 ■ IntroduCIng 2d game development In C#
■ Note monodevelop is an Ide, while monogame framework, or monogame library, is the library that we will be using
throughout this book for building the games. We will be using microsoft visual Studio as the Ide for developing example
projects.
If you wish to learn more about or brush up on the technologies discussed in this chapter, such as C#,
MonoGame, XNA, DirectX, or OpenGL, see the “Technology References” section at the end of this chapter.
Downloading and Installing Development Tools
To use MonoGame and follow along with this book, you will need the Windows 7 or Windows 8 operating system and
three additional pieces of software:
• An IDE: We will be working with the Microsoft Visual Studio IDE. This is the software with
which you will edit, compile, and run your games.
• A game library software development kit (SDK) : We will be working with the MonoGame V3.0
(or higher) SDK. With proper installation, we will be able to access MonoGame functions from
the Microsoft Visual Studio IDE and build our games.
■ Note If you are working on an apple mac machine, you can download the monodevelop Ide instead (url is provided
at the end of this chapter). due to the similarities in the two Ides, you should be able to follow the examples in this book
using monodevelop.
• An asset builder: We will be using XNB Builder for converting formats of assets (images,
audios, fonts) to those that are suitable for your games.
Download and install the IDE: Visual Studio Express
The first piece of software you need is the IDE. To develop in C# and MonoGame, you will need to use either a version
of Visual Studio or MonoDevelop. The examples in this book use Visual Studio 2012 Express. Visual Studio Express
is free to download, and you can find the latest versions, along with optional earlier versions such as Visual C# 2010
Express at the following link:
www.microsoft.com/visualstudio/downloads
All the examples in this book should work in any recent edition of Visual Studio Express, including the 2010 edition.
■ Note through the microsoft dreamSpark program, all full-time students have free access to the professional
version of the visual Studio Ide. all that is required is a school e-mail account. please refer to www.dreamspark.com/
for more details.
Figure 1-1 shows the page for initiating the installation of Microsoft Visual Studio 2010 Express.
2
Chapter 1 ■ IntroduCIng 2d game development In C#
Figure 1-1. Landing page for Visual Studio 2010 Express download
Download and install the game SDK: MonoGame Framework
You will also need the MonoGame framework, which you can download from www.monogame.net/downloads.
Figure 1-2 shows the download page at the time of writing. The version of MonoGame used in this book is V3.0.1
(released March 6, 2013), as indicated at the bottom of the screenshot.
3